Katherine Seeber Photo: NY Dep. of Corrections and Community Supervision

A Queens woman who went to prison for strangling her 91-year-old step-grandmother upstate was killed by her jealous boyfriend, police sources said.

Pedro Sanchez, 38, visited Katherine Seeber, 32, at work about 11 a.m. Tuesday and confronted her about seeing another man, sources said.

He then got into an explosive argument with the victim about 5:35 p.m. yesterday at her Woodside residence on 55th Street—and struck her repeatedly in the face and torso with a blade, sources said.

He began cleaning up the apartment with rags, and putting items from the apartment into an SUV outside.

He bumped into her roommate, and she called 911, sources said. He punched her in the face and stole her cell phone. She began chasing after him, as did other residents.

His brother at some point had also called the police, and said that he had assaulted someone, sources added.

Cops arrested him shortly after near the scene.

He was charged with second-degree murder, criminal possession of a weapon, and tampering with evidence, as well as resisting arrest.

Sanchez, who is homeless, is no stranger to the NYPD. He has a rap sheet of more than 25 busts, including attempted murder, robbery and criminal possession of a weapon, sources said.

He also has a domestic violence history with another woman, sources added.

Seeber served twelve years in prison for killing the nonagerian in Saratoga County, and was released last July. She had claimed that her boyfriend at the time actually murdered the victim while they were burglarizing her home, according to The Saratogian.